I run my headlights (18w LEDs) and run an LED flashing light (16w+/-) when snow blowing. Total amp draw for the lights is probably around 5 amps. After 5-6 hours of run time with the lights on the tractor will have a hard time starting due to the battery being weak. The battery is not that old and works fine when I do not run the lights for extended periods. Is my charging system unusually weak, or this the draw just too much?